TODO: add/edit page for simulations. In add mode, show a list of valid templates (incomplete - rules for determining which templates are valid) that can be instantiated. Specify Enrollment start, end; case start, end.

TODO: list of simulations needs to be sortable by "expected duration" and "recommended group size". We can either add those attributes to "sim_workflows," which would be a new extension table for "workflows," or we can try to use the categories packages. It's worth putting a few hours into categories, but if we don't have something working at that point we should abandon it and use sim_workflows instead.